Cervelo's 2009 S1 is a great
riding road bike with tri-bike capabilities that add value
and versatility.

Review
Note: You’ll see a new look to our reviews for
2009. We’ve built a new studio specifically for
our product photo shoots. The new photos will show greater
detail where we can control color and lighting more
accurately. We can devote more time to photographing
details since we aren’t relying on weather for
good conditions. We hope you find the new
photo format useful. As always, we write and photograph
all our own reviews.

Tri bike or road bike? Which one should you buy? Will any one
bike work for both road and triathlon?

Those are the questions first time buyers ask when torn between
the idea of a more aerodynamic position and better, more efficient
running off a tri bike, but more responsive handling and greater
versatility for group rides on a road bike. Each bike, tri bike
and road bike; has its advantages and disadvantages. Is there
one bike that does it all? Cervelo’s S1 is probably the
one bike that comes closest.

Shown stock on the left, and converted to a triathlon bike
on the right, the 2009 S1 has exceptional versatility as a dual-use
road and triathlon bike with impressive performance in both
configurations.

“Is
there one bike that does it all? Cervelo’s S1 is probably
the one bike that comes closest.”

When considering the differences between road bike and tri
bike it is worth examining the balance sheet of pros and cons
for each bike type:

Road
Bike

Tri
Bike

Advantages

Limitations

Advantages

Limitations

Quick steering optimal for group
rides.

Rider position
is not as aerodynamic as tri bike.

More aerodynamic
body position for solo riding saves significant time.

Not
suited for group riding where road bike riders may be
uncomfortable riding in close proximity to tri bikes due
to slow handling.

Best acceleration to respond
to sudden changes in group ride tempo.

Less comfortable
position/weight distribution for longer rides.

More stable
for high speed, efficient, easy straight line riding.

Some
riders may not climb as well on tri bike as road bike.

Superior high speed cornering
(compared to tri bike, which is more stable).

Generally
less aerodynamic frame configuration on most road bikes.

Easier to
stay in the aero position due to hip angle.

More comfortable
position with better skeletal support of torso for long
rides.

The aerodynamic story of Cervelo is well known.
They started with aerodynamically optimized bikes: Bikes with
valid aerodynamic benefits- not just aero styling- genuine innovations
that make the bike faster. Another part of the Cervelo story
is less conspicuous but equally as innovative.

Most Cervelos use less conspicuous technology that optimizes
specific performance goals. The innovations are subtle, often
hidden, and generally poorly hyped by Cervelo. Most of the benefits
are hidden from a marketing perspective, but become apparent
to the rider after they put miles on the bike.

Cervelo’s 2009 S1 is a treasure trove of hidden engineering
gems that achieve a myriad of subtle design goals. Bottom line:
The S1 has a broad spectrum of capabilities achieved through
small engineering details that result in significant benefits
for the rider. The S1 is a bike of small details that make it
the most versatile aluminum high performance bike available.

“The
S1 is a bike of small details that make it the most versatile
high performance bike available.”

SmartWall 2: The hidden advantage
to Cervelo's aluminum tubing, has been proven in Ironman
triathlons and Tour de France stages. Note the horizontal
internal stiffner added in the bottom bracket area for
improve performance.

The unique tack-welded chainstay bridge that adds stiffness
and durability while relieving stress on the chanstays:
A subtle, elegant engineering advancement. These two sophisticated,
hidden details add significant performance.

The S1 is born from a concept bike that launched an entire
category for Cervelo- the “convertible road/tri bike”,
continuing forward into their current flagship S3 carbon fiber
bike. The S1 is so advanced that, as its previous aluminum version,
the Soloist, it has been ridden in Tour de France stages. Highly
evolved carbon versions have dominated at the Olympic level.
This is not an entry level bike. At $2199 MSRP it is entry level
priced.

The S1 uses Cervelo’s proprietary SmartWall 2 aerodynamic
tubing to achieve light weight, comfortable ride quality, excellent
bottom bracket stiffness and optimal low speed aerodynamics.
Smartwall 2 is a legacy tubeset for Cervelo, proven over and
over in everything from the P3SL to the new P1. It is subtle,
elegant, advanced engineering. Most features of the extrusion
are not visible from the outside of the bike. The proprietary
profile of the tube, typified by the sharp trailing edge, is
the conspicuous feature of SmartWall 2.

The S1 began life as a bike that has gone on
to inspire advanced Cervelo designs raced in the Olympic Triathlon
in Beijing.

The SmartWall 2 downtube on the S1 is substantially thicker
on the sides than on the leading and trailing edge to improve
stiffness while retaining comfort. The bottom line is the bike
accelerates well but soaks up the bumps. Forget what you know
about how aluminum bikes ride. The well conceived geometry combined
with the SmartWall 2 downtube provides a degree of comfort unheard
of in an aluminum road machine. Any question of durability surrounding
aluminum frames has been answered by Cervelo’s lifetime
warranty on this frame.

While the SmartWall 2 tubing is proven engineering it is not
unique to the S1. The features that give the bike “convertible”
geometry from road to triathlon make this bike unique.

The minor, rearward offset
of the bottom bracket enables a wider range of effective
seatpost angles on the S1. This is the feature missing
from standard road bikes.

Firstly, you can’t convert a standard
73 degree-ish seat angle road bike to a triathlon bike
simply by moving the saddle forward to “induce”
a steeper seat tube angle and then bolting on aero bars.
Early attempts at this included the use of forward angled
seatposts. These forward bending seat posts put too much
weight on the front wheel making already responsive road
bike steering downright dangerous. Weight distribution
of the rider wasn’t correct for safe, stabile riding
in the aero position.

A unique feature of the S1 that enables it to be ridden
with aerobars is the rear-offset bottom bracket shell.
The rear offset bottom bracket is the single feature that
makes the S1 so adaptable.

If you look carefully at the seat tube where it plugs
into the bottom bracket shell you’ll notice a distinct
rear curvature of the seat tube into the bottom bracket.
The center of the bottom bracket actually sits behind
the center of seat tube by 40 millimeters. Used in combination
with the carbon fiber variable geometry seatpost the range
of adjustment for the seat angle is well over 3 full degrees,
ranging from 73 degrees to 76 degrees according to Cervelo’s
geometry chart.

Functionally there is the ability to get much steeper
than 76 degrees while still retaining good handling and
stability. We typically use a Profile Tri Stryke saddle
to induce a few more degrees of effective seat angle since
the Tri Stryke is 30 cm long as opposed to the 27 cm long
San Marco Ponza saddle that comes stock on the S1.

Head tube length on the s1 is higher than Cervelo’s P1
and P2 bikes, the pure bred triathlon geometry bikes. That means
getting high enough on the front end of the S1 with aerobars
won’t be difficult but getting very low will require using
a low stack height aerobar, perhaps one that mounts underneath
the drop bars with very low elbow pads along with a low rise
stem.

It is the frame and unique switch-blade geometry of the S1
that make it unique. The component kit is upgraded from previous
years including Shimano’s new ice gray Ultegra SL STI
shifters, front and rear derailleur. The crank is the FSA Gossamer
compact, adding more versatility to the bike with a wide, functional
gear range.

Click on this diagram to see how the
rearward curving seat tube on the S1 makes it more versatile
than a conventional road bike when ridden in the aero position
with aero bars.

Cervelo did use the Mach
2 brake calipers from Tektro on the S1. For reference
this brake is similar to the Tektro R530 caliper sold
under the Tektro label.

Unlike the P1 triathlon bike,
where the brakes are actuated by brake levers without
return springs, I would have liked to see Shimano Ultegra
SL calipers on the S1 since the return spring in the Ultegra
SL STI brake lever is specifically tuned to work with
the Ultegra SL brake caliper. There is a cost associated
with this change since the Tektro/Cervelo brake calipers
would retail for approximately $59.99 and the Shimano
Ultegra SL calipers retail for approximately $139.99.
Is it worth the $80 upgrade? No. There are other places
to put $80 on this bike that would make a more tangible
performance upgrade.

The workman like Shimano R500
wheelset is sturdy, reasonably light and works perfectly
as a do-everything wheelset. 3T Funda fork also shown.

Wheels on the S1 are the tried and true
Shimano R500 Aero wheels shod with the ubiquitous Vittoria
Rubino tire. The tire spec on the S1 has been subject
to change and still appears on Cervelo's website as the
Vittoria Diamante Pro. This, apparently, is the reason
for the line under the bike specifications on Cervelo’s
web page that reads, “Specs may change without notice”.
The older Diamante was a low end tire. The new version
of the Diamante is a 220 T.P.I. (Thread Per Inch) tire
that weighs in at approximately 195 grams according to
Vittoria’s website. Cervelo split the difference
on the tire spec between the old, heavier version of the
Diamante and the newer high end 220 T.P.I. version by
using the Rubino. this is the tire also used on many Felt
models and, while we've never been enamored with its longevity,
it has nice ride quality.

The road version of the Selle San Marco Ponza
is a fine road saddle but won't suit most people riding in the
triathlon position.

The road version of the ubiquitous Selle San Marco Ponza makes
another appearance on the S1 and it is entirely adequate if
not darn nice in the road configuration. When we reconfigured
our S1 for aerobars in the steep seat angle orientation we did
use a Profile Tri Stryke saddle for its additional length and
padding when seated on the nose in the aero posture. The road
version of the Ponza won't cut it as a triathlon saddle for
most people.

The drop handlebar that comes stock on the S1 is truly excellent
with a fine anatomical bend and flats for excellent comfort
along with a very nicely relieved stem. These bars are among
our very favorites.

The S1 comes with a road cockpit built around the excellent
3T Ergonova handlebar and ARX Pro stem. This is a fine set of
controls. The bar uses an interesting ergonomic bulge shape
to increase contact with your hands and improve comfort. It
works- this is the nicest stock road handlebar on any road bike
I’ve ridden. The bars are 7075 aluminum with a short 123
millimeter drop and 77 millimeters of reach front to back. More
importantly, I found the bend and drop to be absolutely perfect
for me when I ran the stem on the P1 bottomed out with no spacers.
This is an elegant way to configure the front end and cuts down
on conversion time switching over to your aero cockpit. Finally,
the 3T Ergonovas are one of a number of new handlebars specifically
designed to work with a Shimano STI lever. The transition from
the tops of the bars to the STI levers is perfect- flat and
wide, plenty of surface area to soak up road shock and provide
good comfort. Cervelo did an excellent job with the controls
and cockpit on this bike. The ARX Pro stem is also oddly nice
for an original equipment stem with nice, skeletonized details
for weight savings and good mounting hardware.

The drivetrain on the S1
is Shimano Ultegra SL, a fine transmission set we reviewed
in excruciating detail here.

This is a versatile gear range
that gives you a top end gear of 122.7 gear inches which
moves the bike 32.1 feet across the ground for every revolution
of the cranks in the biggest gear. By contrast, a traditional
road bike large gear of 53/12 would only provide 119.2
gear inches with a total development of 31.1 feet of development
(distance covered by one crank revolution).

In short, the 50/34 is plenty
of gear for high top speeds but a nice, low gear for easy
climbing. The 34/23 low gear provides a 38.2 inch gear
that travels 12.7 feet every time you turn the pedals.
Contrast that with a typical 39/23 that travels 18.0 feet
for every pedal revolution.

Simply put, less travel is
better at the low end but more travel is better at the
high end. The compact cranks achieve both agendas while
reducing weight and improving shift quality. It is a 100%
win-win component specification that makes a lot of sense
in both the road and triathlon configuration.

To set up the S1 as a steep seat angle triathlon bike you have
a few options for cockpits. You can bolt a low profile aerobar
directly to the stock 3T Ergonova drop bars as long as the bars
are 31.8 mm clamp diameter and you clamp them close to the stem.
The ergonomic shaping of the Ergonovas won’t let you clamp
an aerobar on if it is more than 4 centimeters from the stem
since the bar begins its ovalized, ergonomic shaping. If you
go with this “semi-aero” cockpit it will be a quick
conversion but you won’t have your shifters on your aero
extensions and you’ll have to release your grip on the
aerobars each time you shift which costs time.

The stock cockpit shown on the right, with a new aerodynamic
triathlon cockpit installed on the right.

The best way to set up a nice aerodynamic frame like the S1
for triathlon/time trial specific use is to install an entirely
new aero cockpit. If you cut all your control cable lengths
in advance and do a careful job with your set-up and cable lengths
this could be a 20 minute job changing cockpits if you are handy.
We used the Visiontech aero wing shaped base bar and their excellent
ski bend aerobar with Shimano Dura-Ace 10 Speed bar end shifters
mounted in the tips of the aerobars.

If you decide to make a second triathlon specific cockpit for
your S1 it will cost you the price of the Shimano Dura-Ace bar
end shifters, the FSA VisionTech brake levers, base bars and
aerobars (as our example used). You'll also likely want a cable
set devoted exclusively to this cockpit for easy changes between
the two configurations. Expect to spend about $350-400 for the
components required to have a ready-made full aero cockpit.
This is significantly less than considering the cost of even
an entry level dedicated triathlon bike.

Once the cockpit is in place it is simply a matter of switching
out the seatposts to the forward, steep angle triathlon configuration.
We recommend paying for an additional seatpost permanently sized
and set up in the forward, steep seat angle configuration to
maintain repeatability in your position. Expect about $150-250
for your seatpost configuration including the cost of the new
post and saddle. Now all you do is add your race wheels and
you are ready.

Handling on the bike in both configurations is excellent, with
the road handling being perhaps the most impressive. I had no
issues with stability in the aero position or responsiveness
in the road config. That means you could be attacking on the
Wednesday ride, diving into a corner on the Saturday criterium
and then setting a new time trial or triathlon P.R. on Sunday-
if your legs can equal the capabilities of the bike. It isn’t
difficult to make a bike stable or to make it responsive, but
it is tricky to make it both and that is what Cervelo
has achieved in the S1. It is effectively two bikes in one.

The main triangle of the
S1 features a sloping top tube which is an aerodynamic
compromise but an ergonomic advantage for long torso riders.

There is an additional aspect to the usability
of the S1, especially in the triathlon/aero cockpit configuration.
Since the bike has a sloping top tube it provides additional
stand-over height. This is very nice for long torso riders.
The only flip side to this benefit is the sloping top
tube is, by Cervelo’s own admission, not as aerodynamic
as the parallel top tubes on their dedicated triathlon
bikes like the P1, P2, P3 and P4. It is a small price
to pay for a lot of versatility.

Other frame details include a very durable replaceable seatpost
binder collar and 3T’s Funda aerodynamic carbon fiber
fork. Being a dual use road and triathlon frame this bike has
two bottle mounts in the traditional positions on the down tube
and seat tube. The rear derailleur hanger is fully replaceable
making this a very robust bike with Cervelo’s usual Lifetime
warranty.

Additional main frame details include
traditional dual bottle braze-ons on the down tube and the seat
tube, unlike the triathlon specific P1 which only uses a single
seat tube mount. The bulge chain stays and straight seat stays
along with the proprietary chainstay bridge create a comfortable,
stiff rear end that jumps when you do.

Interestingly, I liken the ride quality of the $2200 MSRP
S1 to Cervelo’s pricey, ultra-lightweight stiffness to
weight ratio carbon bikes. It is snappy and responsive and crosses
bad pavement without excessive road shock. The seat stays are
joined to the frame just below the top tube and may help disperse
road shock while tightening up the rear triangle for lateral
stiffness. It’s a nice combination of features at a reasonable
price. I love riding this bike in both configurations. It is
nimble and angry in the road configuration, and rides with calm
authority in the aero configuration. This would be an ideal
bike for very hilly triathlons where a traditional triathlon
bike may not climb as well, especially out of the saddle. In
that terrain you could simply leave the drop bars and STI levers
in place since most of your shifting will be done on the climbs
while gripping the top section of the drops, not the aerobar.
Again, the possibilities on this bike make it very exciting
as you contemplate different set ups for different terrain and
race courses. The S1 is more than one bike; it is like a full
race team kit of bikes.

Cervelo is one of very few companies to have a truly convertible
geometry dual use bike that makes a nice road bike and a fine
triathlon bike. Given the argument that the P1 can do double
duty as two different bikes it is the thinking mans solution
to the dilemma of buying two separate bikes for group rides
and triathlons.

Versatility and subtle, advanced design features
make the S1 a highly adaptable design that adds value by doing
double duty as a dedicated road bike and fully functional triathlon
bike with additional modifications. It may be the one bike you
ever have to own for road and triathlon!